Electromagnetic control



Dec. 22,1942. w KRAMER 2,306,169

ELECTROMAGNETIC CONTROL Filed Sept. 25, 1940 Inventor I Werner Krfz'tmer, b War/M 2/ 9 His Attorney.

Patented Dec. 22, 1942 UNiTED STATEZE t fit'iiibi'l' QFFICE.

ELECTROMAGNETIC CONTROL Werner Kramer, Karlshorst, Germany, assignor to General Electric Company, a. corporation of New York 7 Claims.

My invention relates to improvements in electromagnetic control and particularly the control of magnetic devices such as relays and the like.

Contact operating devices, such as relays for example, have rebounding tendencies which may frequently result in unsatisfactory contact operation and also damage the contacts by arcing, pounding, etc. It is also often desirable particularly in connection with electromagnetic devices operated by direct current to obtain an accelerated action without the necessity for uneconcmical battery voltages and costly expedients in magnetic constructions such as larger windings of heavier wire, etc.

One object of my invention is to provide an improved electromagnetic control for preventing contact rebounding. A second object of my in vention is to provide an electromagnetic control such that an increased operating effect may be obtained at a predetermined point in the travel of a movable member and particularly where the movement is efiected by an electromagnet. A third object of my invention is to provide an electromagnetic control which does not require costly expedients involving hi her voltage sources and special magnetic and winding constructions. A fourth object of my invention is to provide an electromagnetic control which is inherent in or directly effected by the device to be controlled. These and other objects of my invention will appear more in detail hereinafter.

In accordance with my invention, I provide means operated directly by the device itself for establishing at a predetermined point in the travel of a movable member actuated by the device a supplementary or additional operating effect either to accentuate the movement of the member or positively to maintain the member in some predetermined position without bouncing. Also, in accordance with my invention, I obtain this supplementary effect by means of a precharged condenser which is discharged into an operating winding of the device at a predetermined point in the travel of the movable member of the device. Further, in accordance with my invention, this winding may be the main operating winding of the device especially when the device is energized from a direct current source.

My invention will be better understood from the following description when considered in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the accompanying drawing Fig. 1 illustrates diagrammatically an electromagnetic control arrangement embodying my invention; Figs. 2 and 3 illustrate diagrammatically modifications of the embodiment of my invention shown in Fig. 1; and Figs. 4, 5 and 6 illustrate details of armature constructions for carrying out the embodiments of my invention shown in Figs. 1, 2 and 3.

In Fig. 1 I have illustrated an embodiment of my invention as applied to the electromagnetic control of a device such as an electromagnetically actuated contactor or relay having an energizing winding it, an armature I l and a movable member L. which may be used for any suitable pur pose such as closing contacts lit, for example. Also, as shown in Fig. 1, the winding it is connected in an energizing circuit including a suit-- able source it of direct current and a switch i5 which may be operated either manually or otherwise as will be obvious to those skilled in the art for the purpose of completing the energizing circuit of the winding It to effect an operation of the device.

In accordance with my invention, 1 provide a supplementary operating effect which, as shown, is obtained from a precharged condenser it normally connected across the source I4. In order that this supplementary effect may occur at a predetermined point in the travel of the movable member l2 so that the device itself may directly control the application of this effect, I may provide a circuit controll ng member ll which is arranged through contacts it to connect the precharged condenser H5 directly across the winding It so that the condenser effects a flow of current in the winding ill in the same direction as current flows in this winding when the switch 65 is closed. In order to insure this condenser discharge into the winding Hi, the

energizing circuit thereof includes suitable voltage drop-producing means such as a resistance it. For further control in this respect and in order to avoid the necessity for another switch to control the condenser charger charging circuit, a resistance 20 may be included in the charging circuit of the condenser it. Obviously both the resistances l9 and 26 may be adjustable, desired.

Assuming the parts as shown in Fig. l and that the switch [5 is operated to the closed position, then the operating winding ill is energized to cause actuation of the contact controlling member l2. At the point in the movement of this member at which the contacts iii are bridged by the contact controlling member H the condenser 16 will be discharged into the winding 10 to produce a supplementary effect. This eiiect may be timed either to accelerate the movement of the member I2 or to occur at such a point that, when the contact controlling member l2 engages the contacts I3, the extra force will be available to hold the member against bounc ng. Upon the opening of the switch IS, the parts will return to the position shown in Fig. 1 whereupon the condenser will be charged and ready for another operation.

In the embodiment of my invention shown in Fig. 2, instead of having the condenser I6 connected permanently across the source M through a current limiting means, it is connected through the circuit opening contacts 21 controlled by the circuit controlling member I? when the device is actuated. The operation of this embodiment of my invention is essentially the same as the arrangement shown in Fig. 1 except that both the charging and discharging circuits Of the condenser are controlled by the movable member of the device.

The embodiment of my invention shown in Fig. 3 is analogous to the arrangement shown in Fig. 1 except that the discharge circuit of the condenser is connected to an intermediate point 22 of the winding l8, and similarly the charging circuit of the condenser i6 is connected to an intermediate point 23 of the current limiting resistor 28. In this way a variety of adjustments can be achieved, particularly if the condenser it is also made adjustable.

In accordance with my invention, the condenser I6 is preferably located as closely as possible to the device to be operated in order to reduce the magnitude of the damping effect due to circuit resistance.

In Fig. 4 the armature H is shown as being attracted downwardly toward cooperating magnetic poles 24. Although not shown, it is, of course, to be assumed that suitable retractive means, examples of which are well known to the art, are provided. In this arrangement the armature in its upward position closes contacts Ill and 2| to complete the charging circuit of the condenser through leads 25, 25 after the manner shown in Fig. 2. When the armature i l moves toward the attracted position, it has a limited idle movement a: before it engages the device to be operated such as a valve stem 27 whereupon it engages the contact 18 to complete the discharge circuit of the condenser through leads 25 and 28. In this way the force on the member 2'! to be actuated is directly supplemented by the device itself to insure a positive operation thus enabling a strong follow through movement of the armature in consequence of the discharge current of the condenser.

Since the duration of the idle movement of the armature ll of Fig. 4 represents time lost as far as the operating stroke is concerned and is to be minimized, it is advisable to make the moving parts as light as possible. Thus, as shown in Fig. 5, the armature may be divided into a relatively light part II and a heavier part II". The preliminary or condenser discharge stroke is produced by the armature H which is secured to the member ll. This light armature II will not be saturated by the initial magnetizing current. Subsequently the armature I! travels with the armature H to eiiect the operation of the member 2'! since the discharge current of the condenser saturates the armature member ll so that the armature member ii" is also permeated by the flux.

In the arrangement shown in Fig. 6, I provide a special auxiliary armature H0 which is first attracted upon the closing of the main energizing circuit by the switch I5 to close contacts I and I in the discharge circuit of the condenser. The additional flux to accentuate the movement of the armature II is so materially increased as to eifect a positive movement thereof upon engagement of these contacts.

While I have shown and described my invention in considerable detail, I do not desire to be limited to the exact arrangements shown, but seek to cover in the appended claims all those modifications that fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In combination with an electromagnetic device having a movable member, means for actuating said member, and means for modifying the effect of said actuating means on said member comprising an energizing circuit for said device, a precharged condenser, and means controlled by said device for efiecting the discharge of said condenser through said circuit after a predetermined movement of said member.

2. In combination with an electromagnetic device having a movable member, means for energizing said device to actuate said member, a circuit for energizing said device comprising a normally charged condenser, and switching means controlled by said device for completing said circuit after a predetermined movement of said member to effect the discharge of said condenser in a manner to modify the energization of said device.

3. In combination with an electromagnetic device comprising an energizing winding and a movable armature, a circuit for energizing said winding including a source of direct current, a condenser, a normally closed circuit including said condenser and said source of direct current, and switching means actuated by said armature after a predetermined movement thereof for connecting said condenser to discharge into said winding a current flowing in the same direction as the current flowing in the winding when said energizing circuit is completed.

4. In combination with an electromagnetic device comprising an energizing winding and a movable armature, means for actuating said movable armature and means for energizing said winding after a predetermined movement of said member comprising a normally closed circuit including a condenser and a source of direct current and switching means actuated after a predetermined movement of said member for connecting said condenser so to discharge into said winding as to modify the energization thereof.

5. In combination with an electromagnetic device comprising an energizing winding and a movable armature, a circuit for energizing said winding including a source of direct current, a resistance, and a switch in series, a condenser, a normally closed circuit including said condenser and said source of direct current, and means actuated by said armature after a predetermined movement thlereof for connecting said condenser to discharge into said winding a current flowing in the same direction as the current flowing in the Winding when said switch is closed.

6. In combination with an electromagnetic device comprising an energizing winding and a movable armature, a circuit for energizing said winding including a source of direct current. a

resistance, and a switch in series, a condenser, a normally closed circuit including said condenser and said source of direct current, and means ac tuated by said armature for first opening said normally closed circuit and connecting said condenser to discharge into said winding a current flowing in the same direction as the current flowing in the winding from said source of D. C.

'7. In combination with an electromagnetic device comprising an energizing winding and a 10 

